Portable alarm



Dec. 29, 1959 J. H. BROWN 2,919,318

PORTABLE ALARM Filed July 8, 1957 United States Patent O PORTABLE ALARM John H. Brown, Kansas City, Mo.

Application July 8, 1957, Serial No. 670,499

1 Claim. (Cl. 20061.52)

This invention relates to a burglar alarm and more particularly, to apparatus of such nature which is fully portable and, therefore, adapted for positioning within the path of travel of any door, or for operable connection with a window, to the end that unauthorized entry is detected by virtue of the operation of the signal means forming a part of the alarm.

It is the most important object of the present invention to provide a relatively small, inexpensive, and positively operating burglar alarm that is highly sensitive to the extent that the same is tripped upon the slightest movement being imparted thereto either by a door coming into engagement therewith or the opening of a window to which the alarm is operably connected.

Another important object of the present invention is to provide a portable alarm which embodies a tiltable member capable of closing an electric circuit through a signal device whenever the member is tilted but a slight amount in any direction. i

A further object of the instant invention is to provide a portable alarm embodying a base tiltably supporting a hood or the like, to the end that the electric signal is energized whenever the hood is tilted by virtue of interengagement of a pair of annular, relatively telescoped conduetors secured to the base and the hood respectively.

Other objects include important details of construction, all of which will be made clear or become apparent as the following specification progresses, reference being had to the accompanying drawing, wherein:

Fig. 1 is a perspective view of a portable alarm embodying my present invention illustrating the same in operative use.

Fig. 2 is an enlarged, vertical, cross-sectional view through the alarm.

Fig. 3 is a fragmentary, detailed, cross-sectional view taken on line IlI-III of Fig. 2; and

Fig. 4 is a wiring diagram illustrating the electrical components of the alarm.

As best seen in Fig. 2 of the drawing, a circular base of nonconducting material is circumscribed by an annular conductor 12 rigidly secured thereto. Base 10 in turn supports a tiltable member 14 in the nature of a hood through the medium of an upstanding post 16 of metallic or other electrical conducting material.

Hood 14 is preferably of nonconducting material and has an annular side wall 18 that is in turn provided with an annular boss 20 yintegral therewith and in circumscribing relationship thereto adjacent the lowermost open end of the hood 14. Additionally, the hood 14 has a top wall 22 provided with a central opening 24 that receives the post 16, hood 14 being held against displacement by virtue of the top wall 22 being interposed between a pair of nuts or other abutments 26 and 28 on the post 16.

2,919,318 Patented Dec. 29, 1959 ICC A metallic washer or the like 30, on the post 16 between nut 28 and wall 22, is electrically coupled with an annular conductor 32 by wire means 34. The conductor 32 issecured to the wall 18 of hood 14 within and adjacent the lowermost `open end of the latter in surrounding relationship to the conductor 12 and normally disposed in concentric relationship thereto. Opening 24 in the top wall 22 of hood 14 is suiciently large to permit tilting movement of the hood 14 in all directions to thereby bring the conductor 32 into physical engagement with the conductor 12. Conductors 12 and 32 form a normally open switch and are operably coupled with an electric signal 36 secured to the upper face of base 10 within hood 14 and taking the form of a bell, buzzer, or other signaling means. i

The electric signal 36 is operably connected with conductor 12 by line 38 and with the conductor 32 through the post 16. To this end, a transformer 40 within the hood 14 and mounted on the upper face of base 10, may be coupled with a source of electric energy in the manner shown by Fig. 1 through the medium of an extension cord 42 that extends through the base 10 in the manner illustrated in Fig. 2. Wires 44 and 46 operably couple the transformer 40 with signal device 36 and with post 16 respectively.

A skid-proof element 48 mounted on the lower face of the base 10 may be in the nature of foam rubber, plastic sponge material, or other frictionable substances to impede free sliding movement of the alarm along the oor as shown in Fig. 1 when the alarm is struck by opening of door 50. One or more eyelets 52 may be provided on the annular boss 20 permitting connection of the hood 14 with a window 54 through the medium of a cord or the like 56.

It is manifest from the foregoing that the alarm may be positioned Within the path of travel of door 50 as illustrated in Fig. l, and when operably coupled with a source of electrical energy through extension cord 42, the signal device 36 will be energized forthwith upon any vmovement causing the hood 14 to tilt from the normal position shown in Fig. 2.

More specically, when the door 50-is opened and moved against the boss 20 of the hood 14, the latter is caused to tilt about the supporting post 16, moving the conductor 32 into engagement with the conductor 12. This closes the electric circuit through the signal device '36 as is apparent from both Figs. 2 and 4 of the drawing.

Alternately, `if the alarm is coupled with the window 54 through cord 56 as above described, opening of the winidow 54 by unauthorized persons will cause the hood 14 to tilt, again closing the switch means provided by conductors 12 and 32 and thereby energizing the electric -circuit within which the transformer 40 and the electric signal 36 are interposed.

Having thus described the invention what is claimed :as new and desired to be secured by Letters Patent is:

For an electric, portable burglar alarm having an electric signal device and conductors connecting the signal 1device with a source of electric current; a circuit closer for controlling the passage of electric current through the conductors comprising a base of material incapable lof conducting an electric current; a head member circumscribing the base, said hood member being of material incapable of conducting an electric current, there being -conductors on the base and hood member respectively, .the conductor on the base being a ring and the conductor on the hood member being a ring circumscribing the conductor ring on the base, said conductors on the base and hood being joined to the conductors connecting the device to a source of electric current; and a support of conductive material on the base adapted to normally carry the hood member in a position with its conductor out of Contact with the conductor on the base and to permit swinging movement of the hood member to a position with its conductor in contact with the conductor on the base, said support being provided with a plate of conductive material, there being a conductor of current interconnecting the conductor on the hood and said plate.

UNITED STATES PATENTS Needlman J an. 20, 1953 Robertson Nov. 8, 1955 Toepfer Nov. 22, 1955 Larsen Aug. 7, 1956 FOREIGN PATENTS Germany Nov. 10, 1922 

